Early Kinematic and Thermodynamic Structural Differences Between Developing and Non-developing Atlantic Tropical Convective Systems

Despite numerous improvements in recent years, the formation of a tropical cyclone remains a poorly forecasted event. Beyond issues related to data availability, the forecaster's task is further complicated by the poor understanding of the processes responsible for tropical cyclogenesis. The PREDICT and GRIP field campaigns have provided a new opportunity to gain insight into these processes using unusually dense observations in both time and space.

The present study aims at using these new data sets to perform a detailed analysis of the three-dimensional evolution of both kinematic (e.g. vorticity and divergence) and thermodynamic (e.g. temperature and moisture) in both developing and non-developing tropical convective systems in the western Atlantic. Particular attention is given to the early stages of the system evolution with the goal of identifying fundamental structural differences which may be usefully in determining the likelihood of genesis in an operational setting.

In total, four tropical convective systems are analyzed with this new method. Although the analysis includes only a limited number of cases, the results suggest that there is little kinematic difference between the developing and non-developing systems. In the cases examined the primary difference between developing and non-developing systems is in the distribution of humidity, particularly within the region of mid-level vorticity generation. Additionally, in one non-developing case, differences in the vertical extent of the vorticity column may play a role in the systems evolution.